Lead and Crime: A Poisonous Link

This month, Mother Jones published the results of a surprising investigation into the foul effects of lead in the United States. The article claims leaded gasoline caused a wave of crime in the last century. Crime rates dropped once the lead was removed. The author also says lead causes lower IQs and ADHD.

Journalist George Monbiot was skeptical when he first saw the news. After digging up related academic studies, he published a supportive article in TruthOut. He focused on crime, not on ADHD or IQs.

MIT’s Knight Science Journalism website weighed the evidence and cautions us that other chemicals may be involved and that the connection between lead and violence is not entirely clear. As the article says, there is “no clear biological pathway by which the metallic element lead somehow turns on a violence switch in the human brain.”

A leaded gasoline sign. (Source: HowStuffWorks.com)

I’ve been interested in investigating the link between crime and heavy metal pollution ever since I read a publication which said that researchers had tested biological samples from prison inmates and found that the heavy metal concentrations in their bodies were much higher than that of a control group. This article describes that study and other research on the connection between lead and crime.

Race and income may play a role in kids’ lead exposure. For example, lead pollution tends to be concentrated in lower-income neighborhoods in New Orleans. The maps in the Mother Jones article show income and lead concentrations in these communities.

Based on this evidence, one can reasonably say: if a young person grows up in a lead-polluted community, experiences hardship due to poverty and/or violence, and is more likely to be arrested and judged guilty based on his race and/or income, his likelihood of entering the prison system could become very high.

It is possible that other chemicals in addition to lead may be affecting youth too. We should address these problems when we talk about environmental issues, equal opportunity, and public policy.